ListenerModifier class
A widget that calls callbacks in response to common pointer events.
It listens to events that can construct gestures, such as when the pointer is pressed, moved, then released or canceled.
It does not listen to events that are exclusive to mouse, such as when the mouse enters, exits or hovers a region without pressing any buttons. For these events, use MouseRegion.
Rather than listening for raw pointer events, consider listening for higher-level gestures using GestureDetector.
Layout behavior
See BoxConstraints for an introduction to box layout models.
If it has a child, this widget defers to the child for sizing behavior. If it does not have a child, it grows to fit the parent instead.
{@tool dartpad} This example makes a Container react to being touched, showing a count of the number of pointer downs and ups.
** See code in examples/api/lib/widgets/basic/listener.0.dart ** {@end-tool}
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- SingleChildStatelessModifier
- ListenerModifier
- Available extensions
Constructors
- ListenerModifier({Key? key, Key? modifierKey, Widget? child, PointerDownEventListener? onPointerDown, PointerMoveEventListener? onPointerMove, PointerUpEventListener? onPointerUp, PointerHoverEventListener? onPointerHover, PointerCancelEventListener? onPointerCancel, PointerSignalEventListener? onPointerSignal, PointerPanZoomEndEventListener? onPointerPanZoomEnd, PointerPanZoomStartEventListener? onPointerPanZoomStart, PointerPanZoomUpdateEventListener? onPointerPanZoomUpdate, HitTestBehavior behavior = HitTestBehavior.deferToChild})
-
Creates a widget that forwards point events to callbacks.
const
Properties
- behavior → HitTestBehavior
-
How to behave during hit testing.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- modifierKey → Key?
-
The actual key of the widget, which Modifier wrapped
finalinherited
- onPointerCancel → PointerCancelEventListener?
-
Called when the input from a pointer that triggered an onPointerDown is
no longer directed towards this receiver.
final
- onPointerDown → PointerDownEventListener?
-
Called when a pointer comes into contact with the screen (for touch
pointers), or has its button pressed (for mouse pointers) at this widget's
location.
final
- onPointerHover → PointerHoverEventListener?
-
Called when a pointer that has not triggered an onPointerDown changes
position.
final
- onPointerMove → PointerMoveEventListener?
-
Called when a pointer that triggered an onPointerDown changes position.
final
- onPointerPanZoomEnd → PointerPanZoomEndEventListener?
-
Called when a pan/zoom finishes.
final
- onPointerPanZoomStart → PointerPanZoomStartEventListener?
-
Called when a pan/zoom begins such as from a trackpad gesture.
final
- onPointerPanZoomUpdate → PointerPanZoomUpdateEventListener?
-
Called when a pan/zoom is updated.
final
- onPointerSignal → PointerSignalEventListener?
-
Called when a pointer signal occurs over this object.
final
- onPointerUp → PointerUpEventListener?
-
Called when a pointer that triggered an onPointerDown is no longer in
contact with the screen.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
build(
BuildContext context) → Widget -
Describes the part of the user interface represented by this widget.
inherited
-
buildWithChild(
BuildContext context, Widget? child) → Widget -
A build method that receives an extra
childparameter.override -
createElement(
) → SingleChildStatelessElement -
Create a SingleChildStatelessElement
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children.
inherited
-
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
inherited
-
modified(
) → Modifier -
Available on Widget, provided by the ModifierTransformer extension
Transform normal widget to Modifier -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toDiagnosticsNode(
{String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode -
Returns a debug representation of the object that is used by debugging
tools and by DiagnosticsNode.toStringDeep.
inherited
-
toString(
{DiagnosticLevel minLevel = DiagnosticLevel.info}) → String -
A string representation of this object.
inherited
-
toStringDeep(
{String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String -
Returns a string representation of this node and its descendants.
inherited
-
toStringShallow(
{String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String -
Returns a one-line detailed description of the object.
inherited
-
toStringShort(
) → String -
A short, textual description of this widget.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited